中文说明：该函数用来计算任意函数的一阶偏导数(数值方法),用平面波展开法计算二维声子晶体带隙,研究生时的现代信号处理的作业，包含光伏电池模块、MPPT模块、BOOST模块、逆变模块，匹配追踪和正交匹配追踪，遗传算法无功优化。
English Description：
This function is used to calculate any function of the first order partial derivative (numerical method), using the plane wave expansion method calculation of two-dimensional phononic crystals bandgap, Graduate School of modern signal processing operations, contains a photovoltaic cell module, module of MPPT, boost module, inverter module, matching pursuit and orthogonal matching pursuit, genetic algorithm reactive power optimization.